Composite solid electrolyte with core-shell structure as well as preparation method and application of composite solid electrolyte
By employing a core-shell composite solid electrolyte in lithium/sodium batteries, combining a rigid functional core with a flexible polymer shell in a three-dimensional network, the problems of insufficient ionic conductivity and mechanical strength of existing electrolytes are solved, achieving high-performance battery performance.
Patent Information
- Application Number
- CN202511826823.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-05
- Publication Date
- 2026-03-03
AI Technical Summary
Existing polymer electrolytes in lithium and sodium batteries suffer from problems such as low ionic conductivity, insufficient mechanical strength, and low ion transference number due to high crystallinity. Traditional physical blending methods cannot effectively improve ion transport performance and are prone to dendrite growth.
The core-shell structured composite solid electrolyte is formed by in-situ polymerization of a flexible polymer shell on a rigid functional core to create a three-dimensional continuous ion conduction network, in which alkali metal salts are uniformly distributed. The core is composed of a metal-organic framework material, and the shell is formed by cyanoacrylate monomers.
It achieves high ionic conductivity, high lithium/sodium ion transference number and excellent mechanical strength, solving the performance contradiction that traditional electrolytes struggle to balance, and improving battery safety and cycle stability.
Smart Images
Figure CN121601747A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery technology, specifically to a core-shell structured composite solid electrolyte, its preparation method, and its application. Background Technology
[0002] With the rapid development of electric vehicles and large-scale energy storage industries, the research and development of high-energy-density lithium batteries and low-cost sodium batteries have become two core directions in the field of electrochemical energy storage. However, the development of these two types of battery systems faces the safety hazards brought about by traditional liquid electrolytes, including leakage, combustion, and violent side reactions. The use of solid-state electrolytes is considered a key path to fundamentally solve these problems.
[0003] In solid-state electrolyte systems, solid polymer electrolytes have attracted widespread attention due to their excellent film-forming properties, flexibility, and good electrode interface contact capabilities. However, whether used in lithium-ion batteries or sodium-ion batteries, existing polymer electrolyte matrices (such as polyethylene oxide) share a common technical bottleneck: their high crystallinity at room temperature severely restricts the movement of polymer chain segments, resulting in ionic conductivity that is difficult to meet the requirements of practical applications. Although conductivity can be improved through plasticization, copolymerization, and other methods, these strategies often come at the cost of sacrificing the mechanical strength of the material, making it unable to effectively suppress the growth of lithium or sodium dendrites, thereby causing battery short circuits.
[0004] In addition to the inherent contradiction between electrical conductivity and mechanical properties, existing polymer electrolytes also suffer from low ion transference numbers. This phenomenon leads to severe concentration polarization in both lithium-ion and sodium-ion batteries, not only reducing the battery's rate performance and reversible capacity, but also inducing uneven metal deposition at the negative electrode interface, accelerating dendrite formation, and becoming a major cause of shortened battery cycle life.
[0005] To overcome the limitations of single polymers, the introduction of inorganic fillers to construct composite electrolytes has become a mainstream research direction. However, traditional physical blending methods have significant drawbacks: poor compatibility between inorganic fillers and organic polymer matrices leads to weak interfacial bonding and the formation of significant ion transport barriers; fillers are prone to aggregation, making it difficult to construct continuous ion conduction networks. Particularly noteworthy is the lack of effective control over the transport of lithium or sodium ions by conventional fillers, their inability to selectively promote the migration of target ions, and their difficulty in suppressing dendrite nucleation and growth.
[0006] Therefore, developing a novel electrolyte structure that can be universally applied or adapted to lithium / sodium battery systems and can synergistically solve the "impossible triangle" of ionic conductivity, mechanical strength, and ion transport number has become an urgent need to promote the development of next-generation high-safety and high-performance battery technologies. Summary of the Invention
[0007] The purpose of this invention is to provide a core-shell structured composite solid electrolyte that exhibits high ionic conductivity, high lithium / sodium ion transport numbers, and excellent mechanical strength and interfacial stability at room temperature. Furthermore, this invention also provides a method for preparing the core-shell structured composite solid electrolyte and its applications.
[0008] The first aspect of the present invention provides a core-shell structured composite solid electrolyte, which is composed of a rigid functional core and a flexible polymer shell coated on the surface of the rigid functional core by in-situ polymerization. The rigid functional core and the flexible polymer shell form a three-dimensional continuous ion conduction network, and alkali metal salts are uniformly distributed in the three-dimensional continuous ion conduction network. The rigid functional core is composed of a metal-organic framework material.
[0009] Based on the above technical solution, the metal-organic framework material is zeolite imidazole ester framework nanoparticles.
[0010] Based on the above technical solution, the zeolite imidazole ester framework nanoparticles are cyanofunctionalized ZIF materials formed by coordinating cyanoimidazolium as an organic ligand with zinc ions; the cyanoimidazolium is a compound whose molecular structure contains at least one imidazole ring and one or more cyano groups are directly connected to the imidazole ring.
[0011] Based on the above technical solution, the flexible polymer shell is formed by in-situ polymerization of cyanoacrylate monomers.
[0012] Based on the above technical solutions, the cyanoacrylate monomers have the following general formula structure: CH2=C(CN)COOR Wherein, R represents a straight-chain or branched alkyl, cycloalkyl, or aralkyl group having a C1-C12 organic group.
[0013] Based on the above technical solutions, the cyanoacrylate monomers can be one or any combination of two or more substances selected from methyl cyanoacrylate, ethyl cyanoacrylate, n-propyl cyanoacrylate, isopropyl cyanoacrylate, n-butyl cyanoacrylate, isobutyl cyanoacrylate, tert-butyl cyanoacrylate, n-pentyl cyanoacrylate, and n-hexyl cyanoacrylate.
[0014] Based on the above technical solutions, the alkali metal salt is a lithium salt or a sodium salt.
[0015] A second aspect of this invention provides a method for preparing a core-shell structured composite solid electrolyte, comprising the following steps: Preparation of S1 rigid functional nucleosomes The zinc source and the cyano-containing organic ligand were dissolved in solvents composed of a good solvent and an anti-solvent at a molar ratio of 1:1 to 3, respectively. Two solvents were mixed and stirred at room temperature, and after centrifugation, washing, and vacuum drying, a rigid functional nucleus was obtained. Preparation of S2 electrolyte precursor slurry The rigid functional core is dispersed in an anhydrous organic solvent at a mass percentage of 1-30 wt%, and then alkali metal salts and cyanoacrylate monomers are added and stirred thoroughly to form a uniform and stable precursor slurry. The concentration of the alkali metal salt in the precursor slurry is 0.5~2.0 M, and the mass ratio of the cyanoacrylate monomer to the rigid functional core is 1~10:1. S3 in-situ polymerization and film formation In an initiation environment with a humidity of 10~500 ppm, the precursor slurry is poured onto a substrate, allowing the polymerizable monomers in the precursor slurry to undergo in-situ polymerization. After film formation, the core-shell structured composite solid electrolyte is obtained.
[0016] Based on the above preparation method, in step S1, the volume ratio of the good solvent to the anti-solvent is 10:1 to 1:10.
[0017] Based on the above preparation method, in step S1, the cyano-containing organic ligand is cyanoimidazole, and the cyanoimidazole is a compound whose molecular structure contains at least one imidazole ring and one or more cyano groups are directly connected to the imidazole ring.
[0018] Based on the above preparation method, in step S1, the stirring reaction time is 2 to 24 hours.
[0019] Based on the above preparation method, in step S1, the zinc source is one or a combination of any two or more substances selected from zinc nitrate, zinc acetate, zinc sulfate, zinc chloride, and zinc perchlorate.
[0020] Based on the above preparation method, in step S1, the good solvent is one or a combination of any two or more substances selected from N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone; the antisolvent is one or a combination of any two or more substances selected from methanol, ethanol, acetone, and acetonitrile.
[0021] Based on the above preparation method, in step S2, the alkali metal salt is a lithium salt or a sodium salt; The lithium salt is one or a combination of any two or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium hexafluorophosphate; the sodium salt is one or a combination of any two or more of sodium hexafluorophosphate, sodium bis(trifluoromethanesulfonyl)imide, and sodium bis(fluorosulfonyl)imide.
[0022] Based on the above preparation method, in step S2, the cyanoacrylate monomer has the following general formula: CH2=C(CN)COOR Wherein, R represents a straight-chain or branched alkyl, cycloalkyl, or aralkyl group having a C1-C12 organic group.
[0023] Based on the above preparation method, in step S2, the anhydrous organic solvent is one or more of NMP, DMF, DMAc, DMSO, THF, acetonitrile, and mixed solvents thereof.
[0024] A third aspect of the present invention provides a battery in which the electrolyte is a core-shell structured composite solid electrolyte as described above, or is prepared by the preparation method described above.
[0025] Specifically, the battery is a solid-state battery or a quasi-solid-state battery.
[0026] Specifically, the battery is either a lithium-ion battery or a sodium-ion battery.
[0027] Compared with existing technologies, the present invention has the following beneficial effects: The core-shell composite solid electrolyte of the present invention uses a rigid functional core with rigid properties as a multifunctional filler. The highly polar cyano functional groups on its surface can effectively promote the dissociation of lithium / sodium salts. At the same time, it significantly improves the lithium / sodium ion transference number by selectively anchoring anions. It is coated with a flexible polycyanoacrylate shell formed by in-situ polymerization, which not only provides a continuous and rapid transport channel for lithium / sodium ions and ensures high ionic conductivity, but also crosslinks the isolated rigid functional core into a stable three-dimensional network, giving the electrolyte excellent mechanical properties and dendrite suppression ability. Thus, it has a unique three-dimensional continuous ion conduction network with a cyanofunctionalized zeolite imidazole ester framework as the core and polycyanoacrylate as the shell. Through a multi-level synergistic mechanism, it successfully solves the technical problem that traditional solid electrolytes cannot achieve both high ionic conductivity and high mechanical strength. As a result, it and the battery prepared therefrom have high ionic conductivity, high lithium / sodium ion transference number and excellent mechanical strength and interface stability at room temperature. Attached Figure Description
[0028] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings: Figure 1 This is a three-dimensional structural diagram of the core-shell composite solid electrolyte of the present invention; the diagram is labeled as follows: ZIF-CN core represents a rigid functional core, PECA shell represents a flexible polymer shell, and red and gray dots represent cations and anions of alkali metal salts, respectively. Figure 2The battery performance cycle diagrams are for Comparative Example 1 and the batteries prepared in Specific Examples 1-4. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. The illustrative embodiments and descriptions of this invention are only used to explain this invention and are not intended to limit this invention.
[0030] like Figure 1 As shown, this embodiment of the invention provides a core-shell structured composite solid electrolyte, which consists of a rigid functional core and a flexible polymer shell coated on the surface of the rigid functional core by in-situ polymerization. The rigid functional core and the flexible polymer shell form a three-dimensional continuous ion conduction network, in which alkali metal salts are uniformly distributed. The rigid functional core is made of a metal-organic framework material.
[0031] In specific applications, the metal-organic framework material is zeolite imidazole ester framework nanoparticles.
[0032] In specific applications, the zeolite imidazole ester framework nanoparticles are cyanofunctionalized ZIF materials formed by coordinating cyanoimidazolium as an organic ligand with zinc ions; the cyanoimidazolium is a compound whose molecular structure contains at least one imidazole ring and one or more cyano groups are directly connected to the imidazole ring.
[0033] For example, the cyanoimidazole can be 4-cyanoimidazole, with the following structural formula (1): (1) The cyanoimidazole can also be 4,5-dicyanoimidazole, with the following structural formula (2): (2) In practical applications, the flexible polymer shell is formed by in-situ polymerization of cyanoacrylate monomers.
[0034] In practical applications, the cyanoacrylate monomers have the following general formula: CH2=C(CN)COOR Wherein, R represents a straight-chain or branched alkyl, cycloalkyl, or aralkyl group having a C1-C12 organic group.
[0035] In specific applications, the alkali metal salt is a lithium salt or a sodium salt.
[0036] Meanwhile, this invention also provides a method for preparing the above-mentioned core-shell structured composite solid electrolyte, which includes the following steps: Preparation of S1 rigid functional nucleosomes The zinc source and the cyano-containing organic ligand were dissolved in solvents composed of a good solvent and an anti-solvent at a molar ratio of 1:1 to 3, respectively. The two solvents were mixed and stirred at room temperature. After centrifugation, washing and vacuum drying, a rigid functional nucleosome was obtained.
[0037] In practical applications, the volume ratio of the good solvent to the anti-solvent is 10:1 to 1:10.
[0038] In specific applications, the cyano-containing organic ligand is a cyanoimidazole, which is a compound whose molecular structure contains at least one imidazole ring and has one or more cyano groups directly connected to the imidazole ring.
[0039] In practical applications, the stirring reaction time is 2 to 24 hours.
[0040] In specific applications, the zinc source is one or a combination of any two or more of the following substances: zinc nitrate, zinc acetate, zinc sulfate, zinc chloride, and zinc perchlorate.
[0041] In a specific implementation, the zinc source and the cyano-containing organic ligand are dissolved in a mixed solvent composed of a good solvent and an antisolvent at a molar ratio of 1:1.2~2 in this step. Based on the preparation method of the above embodiments, the good solvent is one or a combination of any two or more substances selected from N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), and N-methylpyrrolidone (NMP); the antisolvent is one or a combination of any two or more substances selected from methanol, ethanol, acetone, and acetonitrile.
[0042] Preparation of S2 electrolyte precursor slurry The rigid functional core is dispersed in an anhydrous organic solvent at a mass percentage of 1-30 wt%, followed by the addition of an alkali metal salt and a cyanoacrylate monomer. The mixture is stirred thoroughly to form a homogeneous and stable precursor slurry. The residual hydroxyl groups, adsorbed water, or coordinated unsaturated metal sites on the surface of the rigid functional core provide potential initiation sites for subsequent polymerization. The concentration of the alkali metal salt in the precursor slurry is 0.5-2.0 M (M is a molar concentration unit, i.e., mol / L), and the mass ratio of the cyanoacrylate monomer to the rigid functional core is 1-10:1. In specific applications, the alkali metal salt is a lithium salt or a sodium salt; wherein the lithium salt is one or a combination of any two or more of lithium trifluoromethanesulfonylimide (LiTFSI), lithium bisfluorosulfonylimide (LiFSI), and lithium hexafluorophosphate (LiPF6); and the sodium salt is one or a combination of any two or more of sodium hexafluorophosphate (NaPF6), sodium bistrifluoromethanesulfonylimide (NaTFSI), and sodium bisfluorosulfonylimide (NaFSI).
[0043] It should be noted that the lithium salt or sodium salt in this embodiment can be selected based on the final application scope. For example, if it is used to prepare lithium batteries, lithium salt is selected, and if it is used to prepare sodium batteries, sodium salt is selected.
[0044] In practical applications, the cyanoacrylate monomers have the following general formula: CH2=C(CN)COOR Wherein, R represents a straight-chain or branched alkyl, cycloalkyl, or aralkyl group having a C1-C12 organic group.
[0045] In specific applications, the anhydrous organic solvent is one or more of N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), acetonitrile, and mixed solvents thereof.
[0046] S3 in-situ polymerization and film formation In an initiation environment with a humidity of 10~500 ppm, the precursor slurry is poured onto a substrate, allowing the polymerizable monomers in the precursor slurry to undergo in-situ polymerization. After film formation, the core-shell structured composite solid electrolyte is obtained.
[0047] In this step, trace amounts of water molecules in the environment are selectively adsorbed and enriched on the surface of the rigid functional core, initiating regional anionic polymerization of polymerizable monomers in the precursor slurry, forming a flexible polymer shell on the surface of the core. As polymerization proceeds, the core and shell structures cross-link with each other and solidify to form a self-supporting composite solid electrolyte membrane with a three-dimensional interpenetrating network structure.
[0048] Finally, this embodiment also provides a battery in which the electrolyte is a core-shell structured composite solid electrolyte as described above, or is prepared using the preparation method described above.
[0049] In practical applications, this battery is a solid-state battery or a quasi-solid-state battery.
[0050] In specific applications, the battery is either a lithium-ion battery or a sodium-ion battery.
[0051] In summary, the core-shell composite solid-state electrolyte and the battery constructed using this embodiment cleverly balance the competing relationships among multiple key performance parameters in solid-state batteries by building a synergistic system of "rigid functional core-flexible polymer shell": the rigid functional core significantly improves ion migration efficiency, the flexible polymer matrix ensures a continuous ion transport path, and the three-dimensional network formed by both endows the electrolyte with excellent mechanical properties. This synergistic effect enables the battery based on this electrolyte to achieve a significant breakthrough in core performance: while maintaining high safety, it also possesses excellent ion conductivity, outstanding cycle stability, and higher energy density. Furthermore, the fabrication process of this embodiment creates favorable conditions for its industrial application, providing a valuable technical path for advancing the practical application of solid-state battery technology.
[0052] The above is the complete content of the present invention. In order to better understand and implement it, the following will provide further explanation and description in conjunction with specific embodiments and comparative examples.
[0053] Example 1 An in-situ battery is prepared by the following steps: Step 1: 2.20 g (10 mmol) of zinc acetate dihydrate was dissolved in 150 mL of N,N-dimethylformamide to form a zinc salt solution, and 1.38 g (15 mmol) of 4-cyanoimidazole was dissolved in 150 mL of methanol to form a ligand solution. The ligand solution was added dropwise to the zinc salt solution, and the reaction was stirred at room temperature for 24 hours. After centrifugation, washing with methanol, and vacuum drying at 60°C, functional nanoparticles were obtained.
[0054] Step 2: The functional particles obtained in step 1 (15% of the total mass of the system), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) (1M), and ethyl cyanoacrylate (50% of the total mass of the system) were mixed in anhydrous N,N-dimethylformamide to form a slurry. This slurry was then cast onto a polytetrafluoroethylene plate and cured in an environment with a humidity of 100 ppm to obtain a self-supporting composite solid electrolyte.
[0055] Step 3: In an argon glove box, using polyanionic NFPP positive electrode as the positive electrode, hard carbon as the negative electrode, and the electrolyte obtained in step 2 as the separator / electrolyte, a trace amount of electrolyte is added and the mixture is packaged into a CR2032 type button cell.
[0056] Example 2: An in-situ battery is prepared by the following steps: Step 1: 2.20 g (10 mmol) of zinc acetate dihydrate was dissolved in 150 mL of N,N-dimethylformamide to form a zinc salt solution, and 1.38 g (15 mmol) of 4-cyanoimidazole was dissolved in 150 mL of ethanol to form a ligand solution. The ligand solution was added dropwise to the zinc salt solution, and the reaction was stirred at room temperature for 24 hours. After centrifugation, washing with methanol, and vacuum drying at 60°C, functional nanoparticles were obtained.
[0057] Step 2: The functional particles obtained in step 1 (15% of the total mass of the system), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) (1M), and methyl cyanoacrylate (50% of the total mass of the system) were mixed in anhydrous methanol to form a slurry. This slurry was then cast onto a polytetrafluoroethylene plate and cured in an environment with a humidity of 100 ppm to obtain a self-supporting composite solid electrolyte.
[0058] Step 3: In an argon glove box, using polyanionic NFPP positive electrode as the positive electrode, hard carbon as the negative electrode, and the electrolyte obtained in step 2 as the separator / electrolyte, a trace amount of electrolyte is added and the mixture is packaged into a CR2032 type button cell.
[0059] Example 3: An in-situ battery is prepared by the following steps: Step 1: 2.97 g (10 mmol) of zinc nitrate hexahydrate was dissolved in 150 mL of N,N-dimethylacetamide to form a zinc salt solution, and 1.38 g (15 mmol) of 4-cyanoimidazole was dissolved in 200 mL of ethanol to form a ligand solution. The ligand solution was added dropwise to the zinc salt solution, and the reaction was stirred at room temperature for 24 hours. After centrifugation, washing with methanol, and vacuum drying at 60°C, functional nanoparticles were obtained.
[0060] Step 2: The functional particles obtained in step 1 (15% of the total mass of the system), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) (1M), and methyl cyanoacrylate (50% of the total mass of the system) were mixed in anhydrous N,N-dimethylacetamide to form a slurry. This slurry was then cast onto a polytetrafluoroethylene plate and cured in an environment with a humidity of 100 ppm to obtain a self-supporting composite solid electrolyte.
[0061] Step 3: In an argon glove box, using polyanionic NFPP positive electrode as the positive electrode, hard carbon as the negative electrode, and the electrolyte membrane obtained in step 2 as the separator / electrolyte, a small amount of electrolyte is added and the mixture is packaged into a CR2032 type button cell.
[0062] Example 4: An in-situ battery is prepared by the following steps: Step 1: 2.97 g (10 mmol) of zinc nitrate hexahydrate was dissolved in 150 mL of N,N-dimethylacetamide to form a zinc salt solution, and 1.38 g (15 mmol) of 4-cyanoimidazole was dissolved in 150 mL of methanol to form a ligand solution. The ligand solution was added dropwise to the zinc salt solution, and the reaction was stirred at room temperature for 24 hours. After centrifugation, washing with methanol, and vacuum drying at 60°C, functional nanoparticles were obtained.
[0063] Step 2: The functional particles obtained in step 1 (15% of the total mass of the system), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) (1.5M), and ethyl cyanoacrylate (40% of the total mass of the system) were mixed in anhydrous N,N-dimethylacetamide to form a slurry. This slurry was then cast onto a polytetrafluoroethylene plate and cured in an environment with a humidity of 150 ppm to obtain a self-supporting composite solid electrolyte.
[0064] Step 3: In an argon glove box, using polyanionic NFPP positive electrode as the positive electrode, hard carbon as the negative electrode, and the electrolyte obtained in step 2 as the separator / electrolyte, a small amount of electrolyte is added and the mixture is packaged into a CR2032 type button cell.
[0065] Comparative example: A basic electrolyte of 1M sodium hexafluorophosphate (NaPF6) + [diethyl carbonate (DEC): ethyl methyl carbonate (EMC): dimethyl carbonate (DMC)] (1:1:1) was used instead of the solid electrolyte. A normal separator was used. Compared with the above four examples, the preparation process of the composite solid electrolyte was omitted, that is, all the previous steps were omitted. The existing electrolyte and separator were used to prepare the comparative sample battery: CR2032 button cell was assembled in sequence with polyanionic NFPP positive electrode, glass fiber separator, and hard carbon negative electrode. Then, 40µL of basic electrolyte was added and the battery was left to stand for 12 hours to complete the preparation of the comparative sample battery.
[0066] The ionic conductivity, electrochemical window, and cycle performance of the batteries prepared in the comparative examples and Examples 1-4 were tested respectively. The comparison results of the relevant electrochemical performance are shown in Table 1 below: Table 1: Ionic conductivity, electrochemical window, and cycling performance at the same time, Figure 2 The battery performance cycling diagrams are for Comparative Example 1 and the batteries prepared in Examples 1, 2, 3, and 4, combined with... Figure 2 As shown in Table 1: By comparing the ionic conductivity, electrochemical window, and cycle performance of Comparative Example 1 with Examples 1-4, it can be seen that the battery prepared using a core-shell structured solid electrolyte has higher ionic conductivity, electrochemical window, and cycle performance than the battery without a solid electrolyte. Compared with conventional basic electrolytes, the in-situ polymerized solid electrolyte forms a core-shell structured polymer network inside. The rigid functional core acts as a skeleton, and the cyano functional groups on its surface act as "anchors," locking anions to facilitate the migration path of sodium ions. The flexible polycyanoacrylate shell acts like muscle tissue wrapping the skeleton, not only constructing a "highway network" for sodium ion conduction but also tightly connecting the dispersed skeleton units into a strong whole, thus simultaneously achieving high ionic conductivity, high mobility, high decomposition voltage, and stronger cycle capability.
[0067] Furthermore, as can be seen from the charts, the ionic conductivity, electrochemical window, and cycling performance of Example 1 are higher than those of other examples. This is because the materials used, the proportions of materials used, the solvents used, the proportions of solvents used, and the preparation conditions are all optimal, resulting in a better cyano-functionalized solid electrolyte, thus leading to a more significant improvement in overall electrochemical performance.
[0068] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A core-shell structured composite solid electrolyte, characterized in that, It consists of a rigid functional core and a flexible polymer shell coated on the surface of the rigid functional core by in-situ polymerization. The rigid functional core and the flexible polymer shell form a three-dimensional continuous ion conduction network, and alkali metal salts are uniformly distributed in the three-dimensional continuous ion conduction network. The rigid functional core is composed of a metal-organic framework material.
2. The core-shell structured composite solid electrolyte according to claim 1, characterized in that, The metal-organic framework material is a zeolite imidazole ester framework nanoparticle.
3. The core-shell structured composite solid electrolyte according to claim 2, characterized in that, The zeolite imidazole ester framework nanoparticles are cyano-functionalized ZIF materials formed by coordinating cyanoimidazol as an organic ligand with zinc ions. The cyanoimidazole is a compound whose molecular structure contains at least one imidazole ring and has one or more cyano groups directly connected to the imidazole ring.
4. The core-shell structured composite solid electrolyte according to claim 1, characterized in that, The flexible polymer shell is formed by in-situ polymerization of cyanoacrylate monomers.
5. The core-shell structured composite solid electrolyte according to claim 4, characterized in that, The cyanoacrylate monomers have the following general formula: CH2=C(CN)COOR Wherein, R represents a straight-chain or branched alkyl, cycloalkyl, or aralkyl group having a C1-C12 organic group.
6. The core-shell structured composite solid electrolyte according to claim 1, characterized in that, The alkali metal salt is a lithium salt or a sodium salt.
7. A method for preparing a core-shell structured composite solid electrolyte, characterized in that, Includes the following steps: Preparation of S1 rigid functional nucleosomes The zinc source and the cyano-containing organic ligand were dissolved in solvents composed of a good solvent and an anti-solvent at a molar ratio of 1:1 to 3, respectively. Two solvents were mixed and stirred at room temperature, and after centrifugation, washing, and vacuum drying, a rigid functional nucleus was obtained. Preparation of S2 electrolyte precursor slurry The rigid functional core is dispersed in an anhydrous organic solvent at a mass percentage of 1-30 wt%, and then alkali metal salts and cyanoacrylate monomers are added and stirred thoroughly to form a uniform and stable precursor slurry. The concentration of the alkali metal salt in the precursor slurry is 0.5~2.0 M, and the mass ratio of the cyanoacrylate monomer to the rigid functional core is 1~10:
1. S3 in-situ polymerization and film formation In an initiation environment with a humidity of 10~500 ppm, the precursor slurry is poured onto a substrate, allowing the polymerizable monomers in the precursor slurry to undergo in-situ polymerization. After film formation, the core-shell structured composite solid electrolyte is obtained.
8. The preparation method according to claim 7, characterized in that, In step S1, the volume ratio of the good solvent to the anti-solvent is 10:1 to 1:
10.
9. The preparation method according to claim 7, characterized in that, In step S1, the cyano-containing organic ligand is cyanoimidazole, which is a compound whose molecular structure contains at least one imidazole ring and has one or more cyano groups directly connected to the imidazole ring.
10. A battery, characterized in that, The electrolyte in the battery is a core-shell structured composite solid electrolyte as described in any one of claims 1-6, or is prepared by the preparation method described in any one of claims 7-10.